Polymers having good manufacturing and performance properties at elevated temperatures are continually in great demand. For example, high heat polymers are useful for replacing metal parts in “under the hood” automotive applications. High heat polymers are capable of withstanding heat on a comparable level as metal parts, but weigh less and so contribute to more fuel efficient automobiles. Other automotive uses further demonstrate a continuing need for high heat polymers.
Lighting reflectors, especially for automotive applications, require materials that can withstand the high heat produced by light sources, that have excellent dimensional stability to focus the light in a tight pattern at long distances, and that can be easily processed into complex shapes. These reflectors are usually coated with a metal, such as aluminum, to provide a highly reflective surface. To achieve this high degree of reflectivity with low haze, a very smooth pre-coated surface is required. In order to consistently achieve such a smooth pre-coated surface, it has typically been necessary to base coat the molded reflector with a primer prior to coating the reflector with metal. Direct metalization of molded parts is also challenging because it introduces the additional requirements of good adhesion of the metal to the molded part and a very smooth surface of the part as molded.
In electronic components there has been a move to leadless solder at least partially because of the deleterious effects caused by lead on the environment. Replacement solders have higher melting points than lead based solders. Thus, polymers capable of withstanding the additional heat necessary to melt the lead replacement solders are needed for use as, for example, substrates or coatings in close proximity to soldering points. Even uses such as polymer parts feeling the heat from jet engine wash, lead to a continuing demand for polymers having higher heat properties than those currently on the market.
Several classes of high heat polymers are known in the art. Polyetherimide resins are known for high heat capabilities with good processability that make their use as coatings, molded articles, composites, and the like very attractive where high temperature resistance is desired.
Polyetherimide resins may be blended with high heat polyetherimide sulfone resins with glass transition temperature above 230° C. to improve thermal performance such as heat deflection temperature and haze onset temperature for surface metalized articles while maintaining good processability. Due to insufficient flow in certain high heat polyetherimide sulfone resins, however, a good balance of thermal properties and flow is required for overall performance of the blends
Thus, there remains a continuing need for polymer compositions having high heat capabilities in combination with those necessary additional properties that allow for good processability in critical application. It is to the provision of such that the present invention is primarily directed.